Hi @costanza,
As you know, margins are (more or less) a function of how many market participants there are. We think the advantages of a properly decentralized betting exchange will bring in players large (market makers/liquidity providers) and small (casual bettors), and margins will tighten up accordingly.
Yes - Live betting on BookiePro will work as per betting exchange standards, including In-Play delays on betting to guard against courtsiding.